How to Use Unix Timestamps: Developer Guide for Dates & Times

September 5, 2026 · 5 min read

Unix timestamps count the number of seconds since January 1, 1970, 00:00:00 UTC. They are the standard way to store and transmit time in software systems because they are timezone-neutral, sortable as integers, and unambiguous. Every developer encounters them, and understanding how they work prevents common date-handling bugs.

What Is a Unix Timestamp

Right now, the Unix timestamp is approximately 1788300000. That number represents the seconds elapsed since the epoch (January 1, 1970 UTC). Timestamps are always in UTC — time zone conversion happens at the display layer, not the storage layer. This prevents the chaos of storing times in different zones.

Common Operations

Convert timestamp to date: divide by 86400 to get days since epoch, or use a converter tool. Get current timestamp: Date.now() in JavaScript (returns milliseconds — divide by 1000 for seconds). Add one day: add 86400 seconds. Add one hour: add 3600 seconds. Subtract two timestamps to get the duration between events.

Milliseconds vs Seconds

JavaScript uses milliseconds (13 digits: 1788300000000). Unix traditionally uses seconds (10 digits: 1788300000). APIs vary — always check whether a timestamp is in seconds or milliseconds. A common bug is treating milliseconds as seconds, which produces dates in the year 58600+.

Time Zone Handling

Store timestamps in UTC. Convert to local time only for display. Never store local time in a database — daylight saving changes, time zone rules change, and users in different zones will see wrong times. Let the frontend handle conversion: new Date(timestamp * 1000).toLocaleString() gives the user's local time.

Try It Now

Our free Timestamp Converter handles this instantly — no signup, no limits.

Also useful: our Base64 Encoder for related calculations.